Prepare an empty glass bottle such as Chili Sauce Glass Packaging. Attach a rope to the neck of the bottle.
Remove the shape that keeps the rope tied and soak it in the lighter oil.
Then tie the rope back to the neck of the bottle and keep the shape of the rope level with the bottom. Ignite the rope and spin the bottle to burn the entire rope. Wait a moment and you will hear a slight crack in the bottle such as Food Grade Glass Honey Jar.
For a further 10-20 seconds, place the neck of the bottle under the faucet and pour the cold water along the place where it was burnt.
Now you have a glass cup, but use a fine sandpaper to smooth the edges before use to avoid hurting yourself.
You can make more bottles that maybe from Sauce Glass Packaging Factory, as beautiful as the picture below.